[@Rune_Alchemist] OH. No, it's quite hard to tell from within the smoke how many are left. There might be a dozen? There might be even two, who really knows. Maybe if someone had a certain magical power with eyes, they'd be able to tell you. ;^D 

Seeing where the light is within the smoke is easier than all the swarming shadows, I'd say. 

All shenanigans aside, if you wanted to take them all out at once, that'd be rather impossible too since they are stepping out from a corridor. Even with a horizontal swing, you'd be only able to hit the ones outside of the smoke without getting the blade stuck in the walls again. Based on that though, and how anytime anyone attacks into the corridor takes more than one thing out, you can assume they are bunched pretty closely. I say you can do like a stab and 'precision' hit one of the remaining lantern dudes if you want a more strategic option. Might even take a few others too as collateral too, with the destructive nature of these weapons. 

I suppose you could also try to bring down the passageway too. But then you'd be missing out on the loots. Oh, the choices...